1. Field of the Invention
The present invention relates to a revolution type actuator that can use its output as a source for driving industrial machines, civil-use machines, and the like which apply a revolution motion.
2. Description of the Related Art
Conventionally, there has been employed such a method as obtaining a revolution motion as an output by using an output transforming mechanism to thereby transform a rotation motion of a stepping motor, a DC (Direct Current) motor, or the like into a revolution motion. On the other hand, however, there has been known such a variable-gap type motor, a variable-reluctance type motor, or the like which revolve their movable element directly, as disclosed in each gazette of the Japanese Unexamined Patent Application Nos. HEI 8-205515 and HEI 11-275851. Those motors utilize an electromagnetic force generated in the same direction as the main magnetic flux, thus featuring a low-speed high-torque rotation.
However, the above-mentioned method for transforming an rotation motion of a stepping motor, a DC motor and the like to a revolution motion by using an output transforming mechanism has suffered from such problems that friction generated at the output transforming mechanism portion deteriorates the efficiency and the apparatus using such a method is difficult to miniaturize. A variable-gap type motor or a variable-reluctance type motor, on the other hand, has a larger gap length than the conventional type DC motor and the like to thus have stronger leakage magnetic flux and a larger gap variation, suffering from a problem of difficulty of high-speed rotation.
In view of the above, it is an object of the invention to provide a revolution type actuator that can directly obtain a revolution motion without using the above-mentioned output transforming mechanism to thereby utilize that output as a source for driving industrial machines, civil-use machines and the like which apply a revolution motion and also that can accommodate a high-speed rotation based on its principle of having no variation in the magnetic gap between its own movable element and fixed element.
To this end, a revolving type actuator having a revolving movable element revolving according to the invention comprises a movable member capable of revolving with respect to a fixed member, a plurality of conducting paths arranged in a plane parallel to a trajectory face of the revolution motion for flowing currents therein a plurality of currents in mutually intersecting directions, a power supply which flows currents having mutually different phases in the plurality of conducting paths, and a magnetic field generator which forms a magnetic field in a direction perpendicular to the conducting paths, in which the movable member revolves by an electromagnetic force generated by an interaction between a current flowing in the conducting path and a magnetic field given by the magnetic field generator. The above-mentioned magnetic field generator may be comprised of a magnet and a stator magnetized by magnetic flux generated by this magnet in such a configuration that the above-mentioned movable member is disposed opposite to the magnetic pole of the magnetic in a plane perpendicular to the magnetic flux interposed between the magnet and the stator and have a conductor attached thereto for forming the conducting path.
The revolution type actuator according to the invention in which the movable member constrained from rotating by a rotation constraining mechanism is revolved with a predetermined revolution radius for driving machines features that at least one conducting path is formed which flows a current on the above-mentioned revolution trajectory face or in a plane parallel to this revolution trajectory face to thereby form a magnetic field perpendicular to the above-mentioned conducting path so that an electromagnetic force generated by an interaction between the above-mentioned current and the electromagnetic force generated by the above-mentioned magnetic field may change the magnitude of the above-mentioned current for thus producing an eccentric revolution motion around a predetermined eccentric shaft, accordingly the revolution axis and the magnetic flux involved in the generation of the electromagnetic force are parallel with each other to thereby eliminate a variation in the gap between the movable member and the stator in principle and so enable designing the gap length sufficiently small within the most advantageous range practically, thus obtaining an excellent effect of being able to accommodate a high-speed rotation, which has been impossible with a prior art revolution type actuator.